The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to form switching power regulator circuits. Many switching regulator circuits were designed to reduce the amount of power delivered to load when the amount of current required by the load decreased. This was often called burst mode or skip cycle mode. When the load again required a higher current, the switching regulator exited the burst mode or skip cycle mode and returned to normal operation. Typically, the transition from the burst mode to the normal operation mode resulted in excessive ripple current in the output voltage supplied by the system using the switching regulator.
Accordingly, it is desirable to have a switching regulator that minimizes the amount of ripple in the output current during the skip-cycle mode, and that minimizes the amount of ripple during the transition from skip-cycle mode back to normal mode.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, or certain N-type or P-type doped regions, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein relating to circuit operation are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action. The use of the word approximately or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to at least ten per cent (10%) are reasonable variances from the ideal goal of exactly as described.